The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
Aspects of the present invention relate to a reciprocating piston mechanism comprising a crankcase, a crankshaft having at least a crankpin, said crankshaft being supported by the crankcase and rotatable with respect thereto about a crankshaft axis, at least a connecting rod including a big end and a small end, a piston being rotatably connected to the small end, a crank member being rotatably mounted on the crankpin, and comprising at least a bearing portion which is eccentrically disposed with respect to the crankpin, and having an outer circumferential wall which bears the big end of the connecting rod such that the connecting rod is rotatably mounted on the bearing portion of the crank member via the big end; wherein the crank member is provided with a crank member gear which meshes with a first auxiliary gear being an external gear, wherein the first auxiliary gear is fixed to a second auxiliary gear via a common auxiliary shaft, which auxiliary shaft is mounted to the crankshaft and rotatable with respect thereto about an auxiliary shaft axis extending parallel to the crankshaft axis, which second auxiliary gear meshes with a central gear having a center line which coincides with the crankshaft axis.
Such a reciprocating piston mechanism is known from EP 0 184 042. The known mechanism comprises a crank member which is driven by the crankshaft through first and secondary auxiliary gears and additional gears.